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Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
no abstracts in English
Asakura, Nobuyuki; Shinya, Kichiro*; Tobita, Kenji; Hoshino, Kazuo; Shimizu, Katsuhiro; Uto, Hiroyasu; Someya, Yoji; Nakamura, Makoto; Ono, Noriyasu*; Kobayashi, Masahiro*; et al.
Fusion Science and Technology, 63(1T), p.70 - 75, 2013/05
Times Cited Count：14 Percentile：72.14(Nuclear Science & Technology)Design study of poloidal field coil (PFC) locations and current distribution for the advanced divertor in the Demo tokamak reactor was presented. Concept of the super-X divertor (SXD) for Demo reactor has an outer divertor leg longer than the conventional divertor, and it extends outboard to increase both the target wetted area and connection length to the outer target (
). Equilibrium calculation code, TOSCA, was developed by introducing two parameters, i.e. super-X null radius (
) and a ratio of the poloidal flux at the super-X null to that at the separatrix (
). Some SXD magnetic configurations with minimal number of PFCs located outside toroidal field coil (TFC) were Demonstrated. Locations of the divertor target were also investigated. It was found that the flux expansion can be increased up to 4-10 depending on the target location and , and that SXD has an advantage to increase with . Thus, the divertor plasma temperature is expected to decrease at the same upstream plasma density. On the other hand, large currents for the divertor PFCs were necessary. Other arrangements of PFCs such as (1) larger and (2) inside TFC, can reduce the PFC currents.
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*; Irie, Yoshiro*
Proceedings of 9th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.538 - 540, 2012/08
Rapid cycling magnets are excited using a resonant circuit and the current waveform is a DC-biased sinusoidal pattern. However, non-linear characteristic of the magnet produces harmonic components in the magnetic field. The harmonic components are different for each type of magnet depending upon the degree of saturation, and it causes a tracking error. This paper proposes harmonic current control in the resonant circuit to reduce harmonic components in the magnetic field.
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
Proceedings of 1st International Particle Accelerator Conference (IPAC '10) (Internet), p.3242 - 3244, 2010/05
In the J-PARC 3 GeV synchrotron, the horizontal closed-orbit-distortion (COD) variation was observed at first of beam commissioning. The COD correction was very difficult to archive because the beam orbit of each shot changes periodically at a period of about 140 seconds. This paper clarifies that the horizontal COD is caused by the switching noise of the dipole magnet power supply and the periodic variation of the beam orbit is caused by the phase sweep of 1 kHz component that include switching noise. Moreover, it has been demonstrate that the dipole magnet power supply using the improved Pulse Width Modulation (PWM) circuit with a synchronized timing system of the accelerator has successfully suppressed the beam orbit variation.
Takayanagi, Tomohiro; Kanazawa, Kenichiro; Ueno, Tomoaki; Someya, Hirohiko*; Harada, Hiroyuki*; Irie, Yoshiro; Kinsho, Michikazu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; et al.
IEEE Transactions on Applied Superconductivity, 18(2), p.306 - 309, 2008/06
Times Cited Count：10 Percentile：50.78(Engineering, Electrical & Electronic)The four shift bump magnets (BUHS01-04) of the 3-GeV RCS in J-PARC, which are located at the long straight section, produce a fixed main bump orbit to merge the injection beam into the circulating beam. They are realized with four magnets connected in series to form the accurate closed bump orbit. However, the total integrated magnetic field of the four magnets is not zero because of the magnetic field interferences between the shift bump magnet and the adjacent quadrupole magnet (Q magnet). In order to decrease the imbalance of the integrated magnetic field, 0.3mm insulators were inserted at the median plane of the return yoke of the second and third shift bump magnets (BUHS02 and BUHS03). The integrated field has been decreased from 2358.0 Gauss-cm to -71.6 Gauss-cm, resulting in the closed orbit distortion of the beam to be decreases from 6.0 mm to less than 1.0 mm.
Takayanagi, Tomohiro; Kanazawa, Kenichiro; Ueno, Tomoaki; Someya, Hirohiko*; Harada, Hiroyuki*; Irie, Yoshiro; Kinsho, Michikazu; Yamazaki, Yoshishige; Yoshimoto, Masahiro; Kamiya, Junichiro; et al.
IEEE Transactions on Applied Superconductivity, 18(2), p.310 - 313, 2008/06
Times Cited Count：2 Percentile：20.19(Engineering, Electrical & Electronic)The beam painting injection system of the 3-GeV RCS in J-PARC, which realizes the uniform beam distributions in the ring, consists of four horizontal paint bump magnets and two vertical paint magnets. Each paint bump magnet power supply is required to excite the current with high accuracy that varies from 17.6 kA to zero during 0.5 msec. The IGBT chopper units, the switching frequency of which is 50 kHz each, are multiple connected to achieve the effective carrier frequency of 600 kHz. The output accuracy is then achieved to be less than 1 %. The measurements of the magnetic field with the actual current waveform were performed and the good performance was confirmed.
Tani, Norio; Watanabe, Yasuhiro; Adachi, Toshikazu*; Someya, Hirohiko*; Igarashi, Susumu*
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.415 - 417, 2006/00
no abstracts in English
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.424 - 426, 2006/00
no abstracts in English
Haga, Koichi; Tani, Norio; Watanabe, Yasuhiro; Someya, Hirohiko*; Adachi, Toshikazu*
Proceedings of 3rd Annual Meeting of Particle Accelerator Society of Japan and 31st Linear Accelerator Meeting in Japan (CD-ROM), p.418 - 420, 2006/00
no abstracts in English
Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Watanabe, Yasuhiro; Someya, Hirohiko*; Sato, Hikaru*; Kishiro, Junichi
IEEE Transactions on Applied Superconductivity, 14(2), p.409 - 412, 2004/06
Times Cited Count：17 Percentile：61.57The 3-GeV synchrotron proposed in the JAERI/KEK Joint Project (J-PARC) is a rapid-cycling synchrotron (RCS), which accelerates a high-intensity proton beam from 400-MeV to 3-GeV at a repetition rate of 25-Hz. The 3-GeV synchrotron is used to produce pulsed spallation neutrons and muons. It also works as an injector for a 50-GeV synchrotron. The 3-GeV synchrotron consists of 24 dipole magnets, 60 quadrupole magnets, 18 sextupole magnets and 52 steering magnets. Since the magnets for the 3-GeV synchrotron are required to have a large aperture in order to realize the large beam power of 1 MW, there is a larger fringe field at a pole end than a usual synchrotron magnet. Therefore, it is important to estimate the magnetic field and the effect of multipole component at the fringe field. In this paper, we report the results of the field calculation and mechanical design of RCS magnets.
Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*; Watanabe, Yasuhiro; Sato, Hikaru*; Kishiro, Junichi
IEEE Transactions on Applied Superconductivity, 14(2), p.421 - 424, 2004/06
Times Cited Count：13 Percentile：54.64The 3-GeV synchrotron proposed in the JAERI/KEK Joint Project (J-PARC) is a rapid-cycling synchrotron (RCS), which accelerates a high-intensity proton beam from 400-MeV to 3-GeV at a repetition rate of 25-Hz. The 3-GeV synchrotron is used to produce pulsed spallation neutrons and muons. Since the magnets for the 3-GeV synchrotron are required to have a large aperture in order to realize the large beam power of 1 MW, there is a larger fringe field at a pole end than a usual synchrotron magnet. In addition, 25-Hz ac field induces an eddy current in magnet components, magnet end plates and etc. The eddy current induced in the end plates is expected to be large. Therefore, it is important to investigate an effect of large leakage field and eddy current to the beam motion around the magnet end part. We have measured the eddy loss and the eddy field at the edges of the dipole and quadrupole magnets. In this paper, we report the comparison between the results of the measurements and the two-dimensional eddy current model developed for this study.
Zhang, F.; Watanabe, Yasuhiro; Koseki, Shoichiro*; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*
JAERI-Tech 2002-039, 21 Pages, 2002/03
The 3 GeV Proton RCS of the JAERI-KEK Joint Project is a 25 Hz separate-function rapid cycling synchrotron under design. Bending magnets (BM) and quadrupole magnets (QM) are excited separately. The 3 GeV RCS requests above 10 families of magnets excited independently, far beyond 3 families in practical RCS's. Difficulty of field tracking between BM and QM is significantly increased Magnet strings are grouped into resonant networks and excited resonantly by power supplies driven by a waveform pattern, typically a DC-biased sinusoidal signal. To achieve a close tracking between many families, the driving signal of each power supply should be adjusted in phase and amplitude flexibly and dynamically.This report proposes a signal generator based on VXIbus. The VXIbus, an extension of VMEbus (VME eXtension for Instrument), provides an open architecture with shared process bus and timing. The VXIbus-based signal generator facilitates the timing synchronization and extension to many channels needed by the 3 GeV RCS. Experimental results of the signal generator are reported.
Tani, Norio; Kanazawa, Kenichiro; Shimada, Taihei; Suzuki, Hiromitsu; Watanabe, Yasuhiro; Adachi, Toshikazu*; Someya, Hirohiko*
Proceedings of 8th European Particle Accelerator Conference (EPAC 2002), p.2376 - 2378, 2002/00
The 3-GeV synchrotron proposed in the JAERI/KEK Joint Project is a rapid-cycling synchrotron (RCS), which accelerates a high-intensity proton beam from 400 MeV to 3 GeV at a repetition rate of 25 Hz. The 3-GeV synchrotron is used to produce pulsed spallation neutrons and muons. It also works as an injector for a 50-GeV synchrotron. Since the magnets for the 3-GeV synchrotron are required to have a large aperture in order to realize the large beam power of 1 MW, there is a large leakage field at an end part than a usual synchrotron magnet. In addition, 25-Hz ac field induces an eddy current in magnet components: e.g. a coil, magnet end plates and etc. We intend to use a stranded conductor as a coil conductor so that the eddy current induced in the coil can be reduced. On the other hand, the eddy current induced in the end plates is expected to be large. Therefore, it is important to investigate an effect of the large leakage field and the eddy current to the beam motion around the magnet end part. We have constructed a prototype dipole magnet and field measurement system for this purpose. This paper reports the results of the design and the preliminary test about this magnet.
Koseki, Shoichiro*; Zhang, F.; Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*
Heisei-13-Nen Denki Gakkai Sangyo Oyo Bumon Zenkoku Taikai Koen Rombunshu, 1, p.253 - 256, 2001/08
no abstracts in English
Watanabe, Yasuhiro; Zhang, F.; Koseki, Shoichiro*; Tani, Norio; Adachi, Toshikazu*; Someya, Hirohiko*
Heisei-13-Nen Denki Gakkai Sangyo Oyo Bumon Zenkoku Taikai Koen Rombunshu, 2, p.761 - 762, 2001/08
no abstracts in English
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
no journal, ,
no abstracts in English
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
no journal, ,
no abstracts in English
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
no journal, ,
no abstracts in English
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
no journal, ,
Watanabe, Yasuhiro; Tani, Norio; Adachi, Toshikazu*; Igarashi, Susumu*; Someya, Hirohiko*
no journal, ,
no abstracts in English
